The Corps of Engineers was still using punch-cards and punch-card slides, for various engineering purposes, into the late 1970's. The most recent asbuilt punchcards I maintained were in a 1980 collection within the National Archives system.
University of Alaska Anchorage had a functioning card-reader miniframe as recently as 1988 - It was gone by '92, but in the 80's, as a tween/teen, I made some spare change by carefully typing hand-written code into punch-cards for college students.
The USAF was still using mainframes into the 1990's, as well. (My dad's office at 11AF DE) switched from a Wang mainframe about 1991... Even as he was receiving a "fast" unix-desktop which took 10-20 hours to calculate air-route environmental impact...
Also, note that Vacuum tube computers are, in fact, far more resilient to both power fluctuation and radiation... which is why they're being looked at again.
https://www.sciencemag.org/news/2012/05/return-vacuum-tube
I read an article in the 1990's about soviet-era mini-tube computers. the tubes were essentially 2D; thicknesses of fractions of an inch.